System for absorbing and distributing side impact energy utilizing an integrated battery pack

ABSTRACT

An energy absorbing and distributing side impact system for a vehicle includes: first and second side sills, each of the first and second sills comprising multiple longitudinal channels, at least an upper longitudinal channel positioned above a vehicle floor panel and at least a lower longitudinal channel positioned below the vehicle floor panel; a battery enclosure mounted between front and rear suspensions of the vehicle, the battery enclosure having a first side member attached to the first side sill, and a second side member attached to the second side sill; cross-members integrated into the battery enclosure; and one or more bolts each extending though a respective opening in one of the cross-members and extending to an opposite side of the vehicle floor panel from the cross-member.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims benefit of the filing date of: U.S.patent application Ser. No. 14/168,351, filed Jan. 30, 2014, U.S. patentapplication Ser. No. 13/308,300, filed Nov. 30, 2011, and U.S.Provisional Application Ser. No. 61/426,254, filed Dec. 22, 2010, thedisclosure of each of which (including material incorporated therein byreference) is incorporated herein by reference for any and all purposes.

BACKGROUND OF THE INVENTION

Modern vehicles use a variety of structures to protect the vehicle'soccupants during a crash. Some of these structures are used to controlthe transmission of the crash energy to the passenger compartment whileother structures, such as seat belts, head restraints, and air bags, areintended to restrain passenger movement during a crash, therebypreventing the passengers from hurting themselves as their bodies reactto the crash forces. Side impact collisions present a particularlychallenging problem to vehicle safety engineers, both due to therelatively low position of the rocker panels on many small vehicles aswell as the difficulty of implementing an impact resistant sidestructure while taking into account vehicle doors and doorways.

U.S. Pat. No. 6,676,200, issued 13 Jan. 2004, discloses an automotivestructure utilizing inner and outer rocker panels, a floor pan joined tothe inner rocker panels, and a plurality of cross-members that extendlaterally across a portion of the vehicle body. The cross-membersinclude energy absorbing extensions designed to absorb side impactloads.

An alternate approach to achieving impact resistance is disclosed inU.S. Pat. No. 6,793,274, issued 21 Sep. 2004, in which an energymanagement system is integrated within various automotive structuralcomponents, e.g., vehicle frames and rails. In particular, the disclosedsystem uses members or inserts that are in some way attached to selectedstructural components of the vehicle, the members designed to bothabsorb and redirect the impact energy encountered during a crash. Thedisclosed members also help to reinforce the components to which theyare attached. The patent describes a variety of ways in which thedisclosed members may be incorporated into a vehicle during themanufacturing process.

U.S. Pat. No. 7,090,293, issued 15 Aug. 2006, attempts to achieveimproved occupant protection through a seat assembly that is designed toprovide side impact rigidity and resistance to rocker override and sideimpact intrusions. The disclosed seat assembly includes a frame track, aframe base slidably engaged to the frame track, a frame back rotatablyengaged to the frame base, and a rear lateral support assembly thatincludes a support frame attached to the rear portion of the frame base.The support frame includes a tubular member that is designed to engagewith a vehicle rocker panel during impact, thereby providing additionalrigidity and strength to the vehicle.

U.S. Pat. No. 8,007,032, issued 30 Aug. 2011, discloses an automotiveenergy absorbing side structure that includes a wide-based B-pillar withan internal reinforcing tube, a rocker with an internal bulkhead, a rearrocker, and at least one cross-member extending inward from the rocker.The disclosed cross-members are designed to transfer impact loads to thefloor, the cross-members and the tunnel brace.

Although vehicle manufacturers use a variety of structures andcomponents to protect a vehicle's occupants during a side impactcollision, typically these approaches provide only limited protectionwhile significantly increasing vehicle weight. Accordingly, what isneeded is a system that provides superior vehicle occupant safety,particularly from side impact collisions, while adding minimal weightfrom impact resistant dedicated structures. The present inventionprovides such a system.

SUMMARY OF THE INVENTION

In a first aspect, an energy absorbing and distributing side impactsystem for a vehicle includes: first and second side sills, each of thefirst and second sills comprising multiple longitudinal channels, atleast an upper longitudinal channel positioned above a vehicle floorpanel and at least a lower longitudinal channel positioned below thevehicle floor panel; a battery enclosure mounted between front and rearsuspensions of the vehicle, the battery enclosure having a first sidemember attached to the first side sill, and a second side memberattached to the second side sill; cross-members integrated into thebattery enclosure; and one or more bolts each extending though arespective opening in one of the cross-members and extending to anopposite side of the vehicle floor panel from the cross-member.

Implementations can include any or all of the following features. Thebattery enclosure is an aerodynamic device has a design that improvesaerodynamic performance of the vehicle. A bottom of the batteryenclosure is substantially flat. Front wheel arch edges on the batteryenclosure are radiused to allow air from a front wheel to transition toan underside of the vehicle. The energy absorbing and distributing sideimpact system further comprising a gasket material that covers a gapformed between a top of the battery enclosure and an underside of thevehicle floor panel. The energy absorbing and distributing side impactsystem further comprising a seat mounting structure on the opposite sideof the vehicle floor panel from the cross-member, the seat mountingstructure held by at least the one or more bolts. The seat mountingstructure further comprises at least one threaded seat mount. The boltis held by a nut on a same side of the vehicle floor panel as the seatmounting structure. The energy absorbing and distributing side impactsystem further comprising a sub-frame mount integrated into the batteryenclosure. The energy absorbing and distributing side impact systemfurther comprising a sub-frame bushing mounted in double shear with astructure on a bottom plate of the battery enclosure. The batteryenclosure is an integral part of a load path for managing loads infrontal impact. The energy absorbing and distributing side impact systemis configured so that a majority of the loads are fed from rails at afront of the vehicle into a torque box. The energy absorbing anddistributing side impact system further comprising a secondary load paththat feeds loads from a lower portion of the vehicle along a sub-frameand into a rear mount of the sub-frame coupled to the battery enclosureand to the torque box. The battery enclosure is configured to feed theloads along its members to the first and second side sills. A bottomplate of the battery enclosure is configured to provide shear stiffnessto mounting locations of a steeling rack, The first side member isattached to the lower longitudinal channel of the first side sill andthe second side member is attached to the lower longitudinal channel ofthe second side sill. Each of the cross-members comprises an upperportion and a lower portion, wherein a spacing between the upper andlower portions is configured to receive a mounting bracket for at leastone battery module in the battery enclosure. Each of the first andsecond side members comprises at least first through fourth lumens,wherein at least the first, second and third lumens are arranged in anessentially vertical configuration, and wherein at least the fourthlumen is arranged outward of the third lumen. The cross-memberssegregate the battery enclosure into full-width sections and at leastone other section, each of the full-width sections fitting two batterymodules side-by-side in a direction of travel, the other section fittingtwo stacked modules.

In a second aspect, an energy absorbing and distributing side impactsystem for a vehicle includes: first and second side sills, each of thefirst and second sills comprising multiple longitudinal channels, atleast an upper longitudinal channel positioned above a vehicle floorpanel and at least a lower longitudinal channel positioned below thevehicle floor panel; and means for improving aerodynamic performance ofthe vehicle, for providing noise and thermal insulation, for providing amounting structure for a seat in the vehicle, for providing anattachment for a sub-frame, for providing a load path for loads in afrontal impact, for providing protection of an occupant in a sideimpact, and for providing stiffness to a mounting location of a steeringrack.

A further understanding of the nature and advantages of the presentinvention may be realized by reference to the remaining portions of thespecification and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 provides a simplified bottom view of an electric vehicle with abattery pack incorporated into the vehicle structure;

FIG. 2 provides a perspective view of a vehicle's undercarriage with thebattery pack incorporated into the vehicle structure;

FIG. 3 provides a perspective view of a portion of a vehicle body andframe with the battery pack separated from the structure;

FIG. 4 provides a perspective view of the battery pack shown in FIGS.1-3;

FIG. 5 provides a perspective view of the battery pack shown in FIGS.1-4, with the top panel removed;

FIG. 6 provides a perspective view of the battery pack shown in FIGS.1-5, this view showing three of the battery modules in place within thepack;

FIG. 7 provides a perspective, cross-sectional view of the battery packshown in FIGS. 1-6 mounted under the floor panel of the vehicle shown inFIG. 3;

FIG. 8 provides a detailed cross-sectional view of one of thecross-members shown in FIG. 7;

FIG. 9 provides a detailed cross-sectional view of an alternatecross-member;

FIG. 10 provides a detailed cross-sectional view of an alternatecross-member;

FIG. 11 provides a detailed cross-sectional view of an alternatecross-member;

FIG. 12 provides a perspective view of the battery pack to rocker panelassembly;

FIG. 13 provides a cross-sectional view of the assembly shown in FIG.12;

FIG. 14 provides a cross-sectional view of a structural support element;

FIG. 15 illustrates the sculpted leading edge of the battery pack inaccordance with the invention;

FIG. 16 provides a perspective view of a sub-frame mount integrated intothe battery pack;

FIG. 17 provides an alternate view of the sub-frame mount shown in FIG.16;

FIG. 18 illustrates a vehicle frontal impact system utilizing thebattery pack;

FIG. 19 provides a side view of the frontal impact system shown in FIG.18;

FIG. 20 illustrates the use of the battery pack to enhance the rigidityof the steering rack mount;

FIG. 21 provides an alternate view from that shown in FIG. 20; and

FIG. 22 provides a cross-sectional view of a seat mounting structuremechanically coupled to the battery pack using structure from FIG. 14.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS

In the following text, the terms “battery”, “cell”, and “battery cell”may be used interchangeably and may refer to any of a variety ofdifferent cell types, chemistries and configurations including, but notlimited to, lithium ion (e.g., lithium iron phosphate, lithium cobaltoxide, other lithium metal oxides, etc.), lithium ion polymer, nickelmetal hydride, nickel cadmium, nickel hydrogen, nickel zinc, silverzinc, or other battery type/configuration. The term “battery pack” asused herein refers to multiple individual batteries contained within asingle piece or multi-piece housing, the individual batterieselectrically interconnected to achieve the desired voltage and capacityfor a particular application. The term “electric vehicle” as used hereinrefers to either an all-electric vehicle, also referred to as an EV,plug-in hybrid vehicles, also referred to as a PHEV, or a hybrid vehicle(HEV), a hybrid vehicle utilizing multiple propulsion sources one ofwhich is an electric drive system.

The present invention integrates a battery pack into an electric vehiclein order to add rigidity to the vehicle structure and significantlyincrease the vehicle's side impact resistance by absorbing anddistributing the impact load throughout the battery pack structure. Toachieve the desired level of structural rigidity, strength and impactresistance, preferably the battery pack is large relative to the overalldimensions of the vehicle and includes multiple cross-members asdescribed in detail below. In a preferred embodiment of the inventionillustrated in FIGS. 1-3, battery pack 101 not only transverses thewidth of the vehicle, i.e., from rocker panel to rocker panel, but alsoextends most of the distance between the front suspension 103 and therear suspension 105. It will be appreciated that while smaller batterypacks may be used with the invention, they may not provide the samelevel of side impact protection, depending upon their size and thenumber of integrated cross-members. In the illustrated embodiment,battery pack 101 is approximately 2.7 meters long and 1.5 meters wide.The thickness of battery pack 101 varies from approximately 0.1 metersto 0.18 meters, the thicker dimension applicable to those portions ofthe battery pack in which battery modules are positioned one on top ofanother, as described further below.

FIG. 4 provides a perspective view of battery pack 101 with the topenclosure panel 401 in place, panel 401 preferably providing asubstantially airtight seal. Hollow side structural elements 403 arealso visible, members 403 preferably including an extended region or lip405 that is used to mechanically and thermally couple the side members403 to the vehicle structure (not shown in this figure). FIG. 5 showsbattery pack 101 with top member 401 removed, this view showingcross-members 501A-501H. The number of cross-members is based on thenumber of cells/cell modules that are to be encased within the batterypack as well as the desired structural characteristics of the batterypack. Preferably battery pack side members 403, including extendedregion 405, battery pack top panel 401 and battery pack bottom panel 505are each fabricated from a light weight metal, such as aluminum or analuminum alloy, although other materials such as steel may be used forsome or all of the battery pack components. Bottom panel 505 may bewelded, brazed, soldered, bonded or otherwise attached to side members403, with the resultant joint between panel 505 and member 403preferably being substantially air-tight as well as being strong enoughto allow bottom panel 505 to support the batteries contained within thepack. Top panel 401 is typically attached to member 403 using bolts orsimilar means, thus simplifying battery replacement as well as allowingbattery interconnects, battery pack components, cooling systemcomponents and other battery pack components to be repaired and/orreplaced.

Cross-members 501A-501H provide several benefits. First and foremostrelative to side impact resistance, members 501A-501H provide mechanicaland structural strength and rigidity to the battery pack and to thevehicle to which the battery pack is attached. Additionally,cross-members 501A-501H help to segregate thermal events by providing athermal barrier between groups of cells as well as minimizing gas flowbetween sections 503, sections 503 being defined by the cross-members,side members 403, top member 401 and bottom member 505. By segregatingthermal events within smaller groups of cells, thermal runawaypropagation is limited as is the potential for battery pack damage.

FIG. 6 shows a similar view to that provided by FIG. 5, with theinclusion of a couple of cell modules 601. In this illustration, asingle module 601 is shown positioned within one of the seven, largersections 503 of battery pack 101. Note that each large section 503 isdesigned to house a pair of battery pack modules 601. Additionally, inthis illustration there are two modules 601 stacked one on top of theother in the front section 507 of pack 101. Note that in the preferredembodiment, each module 601 contains 370 individual cells, each cellutilizing an 18650 form factor. It should be understood, however, thatthis configuration is only exemplary of a preferred embodiment and thatthe invention is equally applicable to other configurations, for exampleutilizing batteries with a different form factor, a larger or smallernumber of cells, individual cells versus modules, etc.

FIG. 7 provides a perspective, cross-sectional view of battery pack 101mounted under floor panel 701 of vehicle 100. This view also providesadditional views of the cross-members. As shown by the cross-sectionalview, in the preferred embodiment cross-members 501A-501H do not utilizethe same cross-section; rather the cross-section of each is optimizedfor each member's location within the pack. In general, cross-members501A-501H may either be comprised of a single unit or, as preferred andillustrated, comprised of an upper member and a lower member. One orboth members may be hollow, thus achieving the desired rigidity andstrength while minimizing weight. It should be understood that not onlycan the configuration/design of the cross-members vary, depending upontheir location within the pack, so can the materials comprising thecross-members. Therefore while cross-members 501A-501H are preferablyfabricated from aluminum or an aluminum alloy, for example using anextrusion process, other materials (e.g., steel, ceramics, etc.) mayalso be used if such materials fit both the mechanical and thermal goalsfor the particular cross-member in question. Additionally, the lumenswithin one or more of the cross-members may be unfilled or filled with ahigh melting temperature, low thermal conductivity material (e.g.,fiberglass or similar materials). Alternately, the lumens within thecross-members may include a liquid (e.g., water), the liquid beingeither stagnant or flowing. If stagnant, the liquid may be containedwithin the lumens themselves or, as preferred, contained within pouchesthat fit within the cavities. If the liquid is flowing, it is preferablycontained within tubing that is inserted within the cross-membercavities and either coupled to a battery cooling system or used in astand-alone circulation system.

In the preferred embodiment, and as illustrated in FIG. 7, cross-members501D and 501E are larger than the other central cross-members. Thereason for the increased size is to provide additional cross-memberstrength at those locations that are most critical to achieving thedesired level of side-impact resistance. As shown in the detailedcross-sectional view of FIG. 8, in the preferred embodimentcross-members 501D and 501E are comprised of an upper member 801 that isattached to battery pack top panel 401 and includes a single lumen 803,and a lower member 805 that is attached to battery pack bottom panel 505and includes a pair of lumens 807 and 809. In this embodiment, member801 is approximately 19 millimeters high, 30 millimeters wide, and has awall thickness of between approximately 2 and 3 millimeters. Member 805is approximately 54 millimeters high, 26 millimeters wide, and has awall thickness of between approximately 2 and 3 millimeters.

Cross-members 501B, 501C, 501F and 510G are slightly smaller thancross-members 501D and 501E, although they retain the basic shape of thelarger cross-members. As shown in the detailed cross-sectional view ofFIG. 9, these cross-members are comprised of an upper member 901 that isattached to battery pack top panel 401 and includes a single lumen 903,and a lower member 905 that is attached to battery pack bottom panel 505and includes a pair of lumens 907 and 909. In this embodiment, member901 is approximately 19 millimeters high, 16 millimeters wide, and has awall thickness of between approximately 2 and 3 millimeters. Member 905is approximately 54 millimeters high, 16 millimeters wide, and has awall thickness of between approximately 2 and 3 millimeters. Note thatthe spacing between upper member 801 and lower member 805, and thespacing between upper member 901 and lower member 905, is used in thepreferred embodiment to capture a battery module mounting bracket (notshown in FIGS. 8 and 9).

Cross-member 501A, located near the rear of battery pack 101 andillustrated in the detailed cross-section of FIG. 10, includes a firstmember 1001 that extends from battery pack lower panel 505 to batterypack top panel 401. Member 1001 is comprised of a large lower section1003 and a small upper section 1005 with respective lumens 1007 and1009. Section 1003 of member 1001 is approximately 54 millimeters high,30 millimeters wide, and has a wall thickness of between approximately 2and 4 millimeters. Section 1005 of member 1001 is approximately 29millimeters high, 13 millimeters wide, and has a wall thickness ofbetween approximately 2 and 3 millimeters. Cross-member 501A alsoincludes a second member 1011 that includes a single lumen 1013 asshown. Member 1011 is approximately 29 millimeters high, 16 millimeterswide, and has a wall thickness of between approximately 2 and 3millimeters.

Cross-member 501H shown in the detailed view of FIG. 11, is located nearthe front of battery pack 101 and between battery pack section 507 andthe adjacent section 503. As section 507 is designed to house twobattery pack modules, one on top of the other, this portion of batterypack 101 utilizes a different design which, in turn, affects the designof cross-member 501H. As shown, cross-member 501H includes an uppermember 1101 that has a single lumen 1103, and a lower member 1105 thathas a single lumen 1107. Member 1101 is approximately 54 millimetershigh, 26 millimeters wide, and has a wall thickness of betweenapproximately 2 and 3 millimeters. Member 1105 is approximately 29millimeters high, 26 millimeters wide, and has a wall thickness ofbetween approximately 2 and 3 millimeters.

FIGS. 12 and 13 provide perspective and cross-sectional views,respectively, that illustrate the attachment of the battery pack 101 tovehicle structural side member 1201. In the preferred embodimentstructural side member 1201 is comprised of a rocker panel, alsoreferred to herein as a sill, which is formed from extruded aluminum oran aluminum alloy (although other materials such as steel may be usedfor members 1201). Preferably a seal or gasket is located between thetop surface 1301 of side members 403 and the bottom surface 1303 of thetop panel 401, thus achieving a substantially air-tight seal. An o-ringgroove 1304 is visible in FIG. 13 for use with such a seal. In theillustrated embodiment, each side member 403 includes four lumens1305-1308. Lower exterior lumen 1308 is positioned under the extendedregion 405 of side member 403. Lumen 1308 is perforated on upper surface1309 and lower surface 1311, the perforations on these two surfacesbeing aligned such that bolts 1313, or similar means, may passcompletely through lumen 1308, thereby allowing bolts 1313 to coupleextended region 405 of member 403 to structural side member 1201 asshown. Bolts 1313 and channel nuts 1315 securely attach side members403, and therefore battery pack 101, to the vehicle's structural members1201. Preferably channel nuts 1315 are held in place during assemblyusing channel nut retainer 1317. In addition to providing a strongmechanical coupling, this approach allows battery pack 101 to be quicklyand efficiently removed from underneath vehicle 101.

FIG. 14 provides a cross-sectional view of a structural support element1400. A bolt 1402 penetrates a metallic sleeve 1404 that is welded tothe structure. Bolt 1402 threads through a nut 1406, for example in across-member of the vehicle structure. This interface is then sealed atmultiple interfaces when the bolt is tightened and provides additionalclamping force to the battery mounts. Here, spacing between an uppermember 1408 and a lower member 1410 is used to capture a battery modulemounting bracket 1412.

FIG. 22 provides a cross-sectional view of a seat mounting structuremechanically coupled to the battery pack using structure from FIG. 14.In some implementations, a battery pack is used for facilitatingthrough-bolting seat mountings. A seat mounting structure 2200 ismechanically coupled to the battery pack on the opposite side of vehiclefloor 1403 by connecting seat mounting structure 2200 to bolt 1402 usingnut 1406. Coupling the seat mounting structure 2200, and thus thevehicle seats (not shown, but attached via threaded seat mount 2202), tothe battery pack provides greatly enhanced seat mount performance. Asshown, the vehicle has a cross-member (i.e., structure 2200) with athreaded sleeve 2202 welded into it which provides the mount which theseat sits on top of and bolts into. From the opposing side and in closeproximity to (as illustrated) or coaxially with the seat mount, a bolt1402 penetrates a metallic sleeve 1404 that is welded to the structure.Bolt 1402 threads through the nut 1406 which is contained in thecross-member 2200 in the vehicle structure. This interface is thensealed at multiple interfaces when the bolt is tightened and providesadditional clamping force to the battery mounts.

FIG. 15 illustrates the sculpted leading edge of the battery pack inaccordance with the invention. In some implementations, a batteryenclosure has an aerodynamic form. In accordance with at least oneaspect of the invention, the battery pack of a vehicle is used as anaerodynamic device for improving the vehicle's overall aerodynamicperformance. In a preferred embodiment, the bottom surface of thebattery pack is flat, or substantially flat, and the front wheel archedges are heavily radiused in order to allow air from the wheel wells totransition from the slow moving wheel arch edges to the underside of thevehicle. FIG. 5 illustrates this aspect of the invention, showing asculpted leading edge 1500 of the battery pack, thereby creating anaerodynamic shape between the front wheel arch and the flat bottom ofthe pack. This design aids the purging of air from within the wheelarch. Note that sculpted front wheel arch edge 501 is also visible inFIGS. 1-3.

FIG. 16 provides a perspective view of a sub-frame mount integrated intothe battery pack. FIG. 17 provides an alternate view of the sub-framemount shown in FIG. 16. In some implementations, a sub-frame mount isintegrated into a battery pack. The purpose of a rubber sub-framebushing is to isolate the passenger compartment from the road inputs aswell as to tune the overall dynamics of the suspension. The ability totune the sub-frame bushing to act predictably in all cases is dependenton the rigidity of its mounting to the vehicle. By mounting a bushingusing one mount surface and a bolt, the bolt and mount location ishighly loaded in single shear. By adding an extra attachment to anothercomponent, this loading can be distributed among additional members andthe mounting becomes stiffer. This in turn increases the performance ofthe bushing by allowing it to be more precisely tuned. In accordancewith the invention, and as illustrated in FIGS. 16 and 17, this goal isachieved by mounting the sub-frame bushing in double shear with a pieceof structure 1600 that is attached directly to the bottom plate of thebattery enclosure. It will be appreciated that structure 1600 may eitherbe separate from the bottom panel 607 of battery pack 601 and designedto be bolted to panel 607, or it may be fabricated as an integral partof the battery pack enclosure. Preferably this aspect of the inventionis combined with a coaxial double screw fixture, thereby allowing thebattery pack and sub-frame structure 1600 to be removed from the vehiclewhile retaining the sub-frame bushing attachment to the body-structure.

FIG. 18 illustrates a vehicle frontal impact system utilizing thebattery pack. FIG. 19 provides a side view of the frontal impact systemshown in FIG. 18. In some implementations, a battery pack is used in afrontal impact system. In a conventional hybrid or electric vehicle, thebattery pack is isolated and not used as a load bearing member thatcontributes to frontal impact performance. In the present invention,however, the battery pack is made strong enough to resist forces fromthe front of the vehicle. Additionally, the battery pack strengthens theoverall ability of the front torque boxes to distribute frontal loadsinto the sills of the vehicle. Accordingly, in another aspect of theinvention, battery pack 601 is used as an integral part of the load pathused for the management of loads in a frontal impact to protect theoccupants during such an event. Preferably, and as shown in FIGS. 18 and19, the majority of the loads are fed from the rails into the fronttorque box. The buckling stability and strength of this torque box issignificantly increased by coupling the battery box in four locations tothis structural member. In addition, a secondary load path feeds loadsfrom the lower portion of the vehicle along the sub-frame and into therear mount of the sub-frame that is coupled to the battery and thetorque box using a single bolt. This allows the loads from a frontalimpact to not only be input into the torque boxes, but into the battery.The battery then feeds the loads along its members to the sill sectionsof the vehicle and also stabilizes the torque boxes in this mode.

FIG. 20 illustrates the use of the battery pack to enhance the rigidityof the steering rack mount. FIG. 21 provides an alternate view from thatshown in FIG. 20. In some implementations, the battery pack is used toenhance steering feel. The rigidity of the steering rack mounting isintegral to providing high quality steering feel, response, and feedbackfrom the road to the driver. In accordance with another aspect of theinvention, and as illustrated in FIGS. 18 and 19, the structure of thebattery pack, and more specifically the thick bottom plate of thebattery pack, is used to provide exemplary shear stiffness in the ydirection to the mounting locations of the steering rack in order toprovide a more rigid and direct connection of the steering rack to thevehicle structure in order to resist opposite loads input from the road.

In a conventional vehicle, it is difficult to achieve the desiredrigidity in the steering rack mounting without adding extra material,and therefore mass. In accordance with the invention, however, the shearstiffness of the bottom panel of the existing battery pack structure isused to stiffen the point at which the steering rack is mounted. Byusing a structure already present in the vehicle, the efficiency of themounting is improved by coupling these components without the added masswhich would be necessary to stiffen the steering rack mounting in aconventional configuration.

In some implementations, mounting the battery pack to the body structureprovides a stiffness multiplier effect. In accordance with anotheraspect of the invention, the battery pack is designed to add not justits own stiffness but a multiple of it to the vehicle's body structure.This multiplier effect has been achieved through the manner in which thepack is mounted as well as the design of the pack which, in particular,is not designed to possess maximum stiffness in its own right, but tointentionally penalize that for the greater benefit of when it isattached to the body structure. This is achieved by balancing therelative thicknesses of the battery pack structure. To achieve themultiplier effect, the structure of the battery pack has beendeliberately compromised as a stand-alone item for significantly greatercontribution when attached to the body structure. That the packcontributes not just its own stiffness but nearly three times that whenattached is of considerable benefit and saves vehicle weight andincreases range.

It should be understood that identical element symbols used on multiplefigures refer to the same component, or components of equalfunctionality. Additionally, the accompanying figures are only meant toillustrate, not limit, the scope of the invention and should not beconsidered to be to scale.

Systems and methods have been described in general terms as an aid tounderstanding details of the invention. In some instances, well-knownstructures, materials, and/or operations have not been specificallyshown or described in detail to avoid obscuring aspects of theinvention. In other instances, specific details have been given in orderto provide a thorough understanding of the invention. One skilled in therelevant art will recognize that the invention may be embodied in otherspecific forms, for example to adapt to a particular system or apparatusor situation or material or component, without departing from the spiritor essential characteristics thereof. Therefore the disclosures anddescriptions herein are intended to be illustrative, but not limiting,of the scope of the invention which is set forth in the followingclaims.

What is claimed is:
 1. An energy absorbing and distributed side impactsystem for a vehicle, the system comprising: first and second sidesills, each of the first and second side sills comprising multiplelongitudinal channels, at least an upper longitudinal channel positionedabove a vehicle floor panel and at least a lower longitudinal channelpositioned below the vehicle floor panel; a battery enclosure mountedbetween front and rear suspensions of the vehicle, the battery enclosurehaving a first side member attached to the first side sill, a secondside member attached to the second side sill, a plurality ofcross-members integrated into the battery enclosure and extendingbetween the first side member and the second side member, a top panel,and a bottom panel, wherein the battery enclosure encloses a pluralityof batteries with all portions of the plurality of batteries residingbelow the vehicle floor panel; and a bolt extending through a firstopening in one of the plurality of cross-members, a second opening inthe vehicle floor panel, and a nut, and extending to an opposite side ofthe vehicle floor panel from the one of the plurality of cross-members.2. The energy absorbing and distributing side impact system of claim 1,wherein the battery enclosure is an aerodynamic device having a designthat improves aerodynamic performance of the vehicle.
 3. The energyabsorbing and distributing side impact system of claim 2, wherein abottom of the battery enclosure is substantially flat.
 4. The energyabsorbing and distributing side impact system of claim 2, wherein frontwheel arch edges on the battery enclosure are radiused to allow air froma front wheel to transition to an underside of the vehicle.
 5. Theenergy absorbing and distributing side impact system of claim 1, furthercomprising a gasket material that covers a gap formed between a top ofthe battery enclosure and an underside of the vehicle floor panel. 6.The energy absorbing and distributing side impact system of claim 1,further comprising a seat mounting structure on the opposite side of thevehicle floor panel from the one of the plurality of cross-members,wherein the seat mounting structure is coupled to the one of theplurality of cross-members by the bolt and the nut.
 7. The energyabsorbing and distributing side impact system of claim 6, wherein theseat mounting structure further comprises at least one threaded seatmount.
 8. The energy absorbing and distributing side impact system ofclaim 1, further comprising a sub-frame mount integrated into thebattery enclosure.
 9. The energy absorbing and distributing side impactsystem of claim 8, further comprising a sub-frame bushing mounted indouble shear with a structure on a bottom plate of the batteryenclosure.
 10. The energy absorbing and distributing side impact systemof claim 1, wherein the battery enclosure is an integral part of a loadpath for managing loads in frontal impact.
 11. The energy absorbing anddistributing side impact system of claim 10, configured so that amajority of the loads are fed from rails at a front of the vehicle intoa torque box.
 12. The energy absorbing and distributing side impactsystem of claim 11, further comprising a secondary load path that feedsloads from a lower portion of the vehicle along a sub-frame and into arear mount of the sub-frame coupled to the battery enclosure and to thetorque box.
 13. The energy absorbing and distributing side impact systemof claim 11, wherein the battery enclosure is configured to feed theloads along its members to the first and second side sills.
 14. Theenergy absorbing and distributing side impact system of claim 1, whereina bottom plate of the battery enclosure is configured to provide shearstiffness to mounting locations of a steering rack.
 15. The energyabsorbing and distributing side impact system of claim 1, wherein thefirst side member is attached to the lower longitudinal channel of thefirst side sill and the second side member is attached to the lowerlongitudinal channel of the second side sill.
 16. The energy absorbingand distributing side impact system of claim 1, wherein the one of theplurality of cross-members comprise an upper portion and a lowerportion, wherein a spacing between the upper and lower portions isconfigured to receive a mounting bracket for at least one battery modulein the battery enclosure.
 17. The energy absorbing and distributing sideimpact system of claim 1, wherein each of the first and second sidemembers comprises at least first through fourth lumens, wherein at leastthe first, second and third lumens are arranged in an essentiallyvertical configuration, and wherein at least the fourth lumen isarranged outward of the third lumen.
 18. The energy absorbing anddistributing side impact system of claim 1, wherein the plurality ofcross-members segregate the battery enclosure into full-width sectionsand at least one other section, each of the full-width sections fittingtwo battery modules side-by-side in a direction of travel, the othersection fitting two stacked modules.
 19. The energy absorbing anddistributing side impact system of claim 1, wherein the bolt furtherextends through a sleeve in the one of the plurality of cross-members.20. The energy absorbing and distributing side impact system of claim 1,wherein the battery enclosure is coupled to a torque box.